Postretirement Benefits Other Than Pensions - Schedule of Net Periodic Benefit Costs for Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 404	$ 397	$ 495
Interest cost	726	752	789
Amortization of prior service credit and recognized actuarial (gain) loss	448	320	308
Other	0	48	0
Net periodic benefit cost (income)	1,578	1,517	1,592
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Service cost	103	118	308
Interest cost	680	864	1,198
Amortization of prior service credit and recognized actuarial (gain) loss	(1,930)	(2,441)	(1,672)
Other	0	0	5
Net periodic benefit cost (income)	$ (1,147)	$ (1,459)	$ (161)